docstr: Add a duration to an Epoch.
  
  = INPUT VARIABLES
  - rhs    The Epoch to subtract.
  
  = RETURN VALUE
  - Returns the difference of ourselves and the input Epoch.
docstr_tok: ["Add","a","duration","to","an","Epoch",".","=","INPUT","VARIABLES","-","rhs","The","Epoch","to","subtract",".","=","RETURN","VALUE","-","Returns","the","difference","of","ourselves","and","the","input","Epoch","."]
code: def __add__(self, rhs):
      """Add a duration to an Epoch.
  
      = INPUT VARIABLES
      - rhs    The Epoch to subtract.
  
      = RETURN VALUE
      - Returns the difference of ourselves and the input Epoch.
      """
      t = self
      if self._frame != rhs.frame():
          t = self.convert(rhs._frame)
  
      sec = t._seconds + rhs.seconds()
  
      return Epoch(t._frame, sec, t._jd)
  
file_path: catboost/contrib/python/matplotlib/py2/matplotlib/testing/jpl_units/Epoch.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import six
  import math
  import datetime
  from matplotlib.dates import date2num
label_desc: Use image node_id 7 for calling the Epoch obj's underlying member method code with example usage: obj.__add__(rhs) and returns: Epoch